Method and device for measuring actuators in a projection exposure apparatus for semiconductor lithography

The invention relates to a method for measuring an actuator (38.2) in a projection exposure apparatus (1, 21) for semiconductor lithography, in particular in a projection lens (9, 27), wherein two actuators (38.1, 38.2, 38.3) are mechanically coupled to one another, comprising the following method steps: - driving and deflecting a first actuator (38.2) with a constant control signal and deflecting a further actuator (38.1, 38.3) by way of the mechanical coupling, - determining the capacitance of the further actuator (38.1, 38.3), which was deflected by way of the coupling. Furthermore, the invention relates to a projection exposure apparatus (1, 21) and a projection lens (9, 27) for semiconductor lithography, the latter thereof comprising a device for measuring at least two mechanically coupled actuators (38.1, 38.2, 38.3), comprising a control device (40) and a measuring device (43), wherein the measuring device (43) is configured to determine the capacitance of at least one actuator (38.1, 38.2, 38.3).